Existing methods for keeping lines unfrozen may include the use of heat tape, recirculating lines, heated lines, weep systems (in which water is run continuously or intermittently through lines), air purge, and/or liquid antifreeze injection. Such methods may serve to prevent freezing of lines, but often suffer from high operating costs, wastefulness, high-energy demand, dangerousness, unreliability, and/or high expense for the related equipment. There exists a need in the art for improved systems and methods for antifreeze foam injection.